[TenTec] QSK or not?
Bob McGraw - K4TAX
RMcGraw at Blomand.net
Mon Mar 17 20:26:39 EDT 2014
The biggest problem, as I understand, comes from operators using a non QSK
qualified amp in a QSK mode. At this point one can expect relay failure due
to hot switching.
As most amps do have the provision for monitoring SWR I suggest monitoring
the SWR indication for an indication of hot switching. After tune up
typically one will have low SWR.. If during keying one observes a higher
SWR value they can be assured that hot switching is taking place within the
amp. If this is the case, be assured the relays are taking a beating
electrically and will likely soon need attention.
Do note the same situation when operating VOX. Most radios provide some
degree of key-up delay when in CW but there is typically no delay during SSB
operation. Thus when the voice activates the VOX there is RF applied to the
amp without any delay. I find this to be a sure bet for realy hot
----- Original Message -----
From: "GARY HUBER" <glhuber at msn.com>
To: "TenTec Reflector" <tentec at contesting.com>
Sent: Monday, March 17, 2014 10:39 AM
Subject: [TenTec] QSK or not?
I operate QSK and have the past thirty years using TenTec equipment.
One reason given by others for not running QSK is that the relays wear out
sooner in the transceiver and amplifier.
How Long will the Relays Last?
What kind of life can you expect from the relays? The relay life is
specified at 100
million operations minimum at 36,000 operations/hour. The service life
increases as the
operations/hour decreases. So let’s use the standard PARIS text that is used
determining code speed.
PARIS has 10 dits and 4 dahs = 14 relay operations/minute at 1 WPM.
Assuming an average of 25WPM code speed, you would have 360 relay operations
minute. So, 100 million operations = 4630 hours. Now you normally operate
transmitting and 50% receiving during a QSO, so your relay operating time
double to 9260 hours. There are 8760 hours/year, which means you could
years at 25 WPM before the relays exceeded their lifetime spec – IF you
hours/day! But when you operate, you are probably listening more like 75% of
and in a QSO 25% of the time. So this says that your relay operating life
will be over 4-
years if you operate 24 hours/day. So what do you normally average in
time/day? I bet it is not more than about an hour/day. But let’s say you
hours/day of operation (i.e. you are not married and have no kids, you don’t
shop or eat
or sleep much, and you don’t hold a full-time job). So the relay life will
extend to about
25 years! The bottom line - Don’t worry about wearing out the relays anytime
73 ES DX,
Gary – AB9M -...-.-
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